Java ReentrantLock example 2017-06-25 09:11
ReentrantLock and synchronized keyword both can make sure only one thread execute the code on the same time. They are similar but not the same. ReentrantLock is more flexible than synchronized. In this page I will show you a simple use case of ReentrantLock.
Worker.java
public class Worker {
private static Lock lock = new ReentrantLock();
private static int count = 0;
public void execute(long time) {
Thread thread = Thread.currentThread();
lock.lock(); // current thread get the lock
System.out.println("this is: " + thread.getName() + " current count:" + count++);
lock.unlock();// current thread release the lock
try {
Thread.sleep(time);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
Client.java
public class Client {
public static void main(String[] args) {
Worker worker = new Worker();
new Thread(){
@Override
public void run() {
while (true){
worker.execute(3000);
}
}
}.start();
new Thread(){
@Override
public void run() {
while (true){
worker.execute(3000);
}
}
}.start();
}
}
We start two threads to print out the thread name and the number of count. ReentrantLock makes sure only one thread is printing on the same time. One thread will be blocked until getting the lock.